Re: Is this true: Earth's magnetic field is collapsing, scientists say

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From: Ronald Wong (ronwong@inreach.com)
Date: Tue Jul 20 2004 - 23:20:42 PDT 

Message-Id: <l03102802bd234aa40263@[209.209.19.180]>
Date: Tue, 20 Jul 2004 23:20:42 -0700
From: Ronald Wong <ronwong@inreach.com>
Subject: Re: Is this true: Earth's magnetic field is collapsing, scientists say

Recently, Sue posted an article from the New York Times on Pinhole which
had a headline that read:

>"Earth's magnetic field is collapsing, scientists say
>
>Change will wreak havoc -- but not for about 2,000 years
>
>Tuesday, July 13, 2004
>
>By WILLIAM J. BROAD
>
>THE NEW YORK TIMES"
>
>...rest of the article...

Sue:

Despite the claims in the news article (it IS the New York Times), I think
you should know that a new model of the way the earth interacts with the
solar wind plasma would seem to indicate that we, or whoever/whatever will
be around at the time, won't have anything to worry about if/when the
earth's magnetic field drops below 10% of its normal strength. Something it
apparently has done in the past for periods lasting thousands of years at a
time.

Guido Birk, in collaboration with Harold Lesch and Christian Konz, studied
the interaction of the magnetized, fully ionized solar wind plasma (a
million km/hr stream of hydrogen and helium nuclei) with the unmagnetized,
partially ionized ionosphere of the Earth.

Using kinematic estimates and 3-dimensional plasma-neutral gas simulations.
They found that ...

"...the relative motion between the solar wind plasma and the ionosphere
results in the self-generation of magnetic fields in the ionospheric
layer." ...
"...For a reasonable shear length of L = 10 km the maximum strength of the
newly generated magnetic field is comparable to the one of the present
dipole field. Consequently, even in the case of a complete breakdown of the
Earth's dynamo, the biosphere is still shielded against cosmic rays, in
particular coming from the sun, by the magnetic field induced by the solar
wind."

(From the journal "Astronomy and Astrophysics", vol. 420 No. 2 June III
2004 p L15-L18 - a few weeks before Mr. Broad's article appeared in the NYT)

This is fine for the bioshpere but it offers no comfort for any astronaut
or satellite orbiting the earth. Nothing is said about the effect on the
ozone layer but, for those who presently use the earth's dipole field as an
aid in navigation, this new magnetic field will be of no assistance. The
"self-generated magnetic field" is non-dipole in nature.

Cheers.

ron

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